Question

I am not sure as to why that redirection provided in the code does not work. Every time I run the script, the output file is always empty. Does anyone have an idea on that?

Thanks.

#!/bin/sh

LOOK_FOR="DefaultProblem"
FILES=`ls plugins/*source*.jar`

for i in $FILES
  do
    # echo "Looking in $i ..."
    unzip -p $i | grep -i $LOOK_FOR > output #> /dev/null 
    if [ $? == 0 ]
    then
      echo ">>>> Found $LOOK_FOR in $i <<<<"
    fi
  done

Answer 1

You may want to use >> (append) instead of > (overwrite) for redirection as:

unzip -p $i | grep -iF "$LOOK_FOR" >> output

Since you’re executing this command in a loop and overwriting file output every time, it might be blank in the end if very last command with grep doesn’t find any matching line in unzip output.